I'd get it checked. i had the mirena for three years before i got it taken out so we could have our second. i never had any pain except for the initial cramping. i'd get a little crampy around my periods which eventually disappeared (as did the cramps and i get horrible, knock me on my *** cramps).

it was really low maintenance for me and i loved it, but i also know that not everyone is the same and if i were having pain, i'd want that checked by a doc. there are risks involved with anything and i don't think you should be having pain (what kind of pain is it?).